“Always the villain, even when I'm not.”

Regina Mills is the daughter of Cora and Henry. She becomes the second wife of King Leopold and the step-mother of Snow White. She is later known as The Evil Queen, the main antagonist of the series.

Regina loves Henry with all her heart but has a evil way of showing it. She has the entire town afraid of her and rules with an iron fist. Her heart has been darkened from the evil she has had to endure her entire life and it has made her the person she is today, so full of evil and hatred. She is the one who inflicted the curse.

Spoilers Ahead!!!

As a young woman, Regina's mother Cora sets up Regina's marrying King Leopold, killing her true love Daniel to prevent her running off with him. Since Snow revealed to Cora Regina's attraction to Daniel, Regina vowed to destroy Snow's happiness to avenge her lost happy ending.

While preparing for her wedding, she meets Rumplestiltskin who teaches her magic and promises to help her be rid of her mother, eventually sending Cora through a looking glass. She remains unhappy in her loveless relationship, so obtains control of a Genie and uses him to kill the King, making her ruler of Leopold's realm.

As an older Snow White and Prince Charming take back the kingdom, The Evil Queen is banished, later being informed by Rumplestiltskin that she could harm Snow and Charming if they were in another world. On the day of the couple's wedding, The Evil Queen vows to cast a curse on the inhabitants of the Enchanted Forest that will take away their happiness. She must use the heart of the thing she loves most to enact the curse. Understanding this to be her father Henry, she cuts out his heart and casts the curse.

In Storybrooke, she is (Mayor) Regina Mills. With Mr. Gold (Rumplestiltskin)'s assistance, she adopts Henry Mills as a baby, not knowing that he is the grandson of Snow White and Prince Charming. Her relationship with Henry is strained as he prefers the company of his birth mother Emma Swan. Regina is determined to convince Henry that his theory about the curse is false, starting him on regular sessions with therapist Dr. Archie Hopper (Jiminy Cricket).

She has a sexual relationship with Sheriff Graham Humbert (The Huntsman), but crushes his heart when he breaks up with her, revealing that he remembers her identity as The Evil Queen.

The power struggle between Regina and Rumplestiltskin continues in Storybrooke where she is constantly at odds with Mr. Gold. He assists Emma defeat Regina's candidate for Sheriff. Unbeknownst to him, Regina is holding Belle, Gold's true love, captive underneath the Storybrooke Hospital.

She tries to prevent the relationship between David Nolan (Prince Charming) and Mary Margaret Blanchard (Snow White), by reuniting David and his wife Kathryn Nolan (Princess Abigail). When the pair start an affair, she uses this to discredit Mary Margaret after the Nolans' marriage falls apart. After Kathryn goes missing, Mary Margaret is set up and arrested for her apparent murder. Regina is upset when Gold returns her alive.

Emma tells Regina she knows the truth and declares her intentions to get Henry back. She then makes an apple turnover to poison Emma, but Henry willingly eats it instead, falling under a sleeping curse and ultimately making Emma realize the curse's reality. Henry dies shortly after, only to be awoken by true love's kiss from Emma, also breaking the curse.

Upon realizing their true identities, Mr. Gold summons a wraith to suck out Regina's soul in retaliation to her abducting Belle. It is sent through a portal into the Enchanted Forest, though Emma and Mary Margaret fall through as well. Henry is heartbroken, telling Regina he never wishes to see her again until she returns them to Storybrooke.

Regina later takes back Henry after reclaiming her magic, but realizes that she is behaving like her mother to force Henry to stay with her; she offers to let Henry live with David. Later, Dr. Whale reanimates Daniel (Regina's true love)'s corpse but he becomes a mindless monster. He urges Regina to move on and love again, who then turns him to dust, seeking consolation in Archie Hopper. When her mother arrives in Storybrooke, Cora convinces Regina to look for The Dark One's dagger to control and force him to kill their enemies, leaving her innocent in Henry's eyes.

Cora later dies during the fight to protect Mr. Gold, with Regina holding Mary Margaret accountable. Captain Hook warns Regina about newcomers Greg Mendell and Tamara, who offered him a deal to assist them take magic from Storybrooke. He tells Regina that he can assist her by betraying the outsiders and offering his services. Regina agrees and tells Hook that Storybrooke has a fail-safe trigger that will destroy the town, enabling her to escape with Henry. Hook betrays her, and she discovers that Greg Mendell is in fact (Owen Flynn), a boy she befriended at the beginning of the curse, who has returned to find his father that went missing after Regina had him arrested. Greg and Tamara activate the trigger to destroy Storybrooke, but Regina and Emma stop them. Henry is then captured by the pair and taken to Neverland. Regina travels with Emma, Mary Margaret, David, Mr. Gold, and Hook, eventually managing to rescue Henry from the evil Peter Pan, and return to Storybrooke. However, Pan enacts Regina's curse once more, forcing her to reverse the original curse returning her and the remaining inhabitants to their original worlds while Emma and Henry escape to New York City.

Back in the Enchanted Forest, Regina struggles to come to terms with the loss of Henry, though Mary Margaret and Robin Hood persuade her to move forward. Regina soon learns she is half-sisters with Zelena, the Wicked Witch of the West. To save them from Zelena's threats, Regina helps Snow and David enact a new curse to return to Storybrooke, before Zelena adds a forgetting potion to it. With no memories of the past year, Regina faces the struggle of Henry's lost memories of her in Storybrooke until his book restores his memories and she breaks the curse with true love's kiss, restoring the residents' memories of the past year. She meanwhile forms a bond with Robin Hood, which turns romantic after she learns he is her soul mate.

Zelena later obtains Regina's heart as an ingredient in her scheme to change the past, though Regina uses her newly discovered light power to defeat her. After Emma and Hook are dragged into Zelena's time portal, they inadvertently return with Maid Marian, who was originally sentenced to death by Regina. To the anger of Regina, Marian, Robin, and Roland are reunited. Regina later seeks to discover the writer of Henry's book. After Maid Marian was hit with a freezing spell that the Snow Queen put in her ice cream cone, Regina and Henry had to remove her heart until Regina can find a way to break the spell.